An endoscope is an elongated, tubular structured medical device that is inserted into body cavities to facilitate visualization and examination by medical professionals. The endoscope includes a telescope with an objective lens at its distal end. The telescope includes an image-forwarding system, which in rigid endoscopes is typically a series of spaced-apart lenses. In flexible endoscopes, typically, the image-forwarding system is a bundle of tiny optical fibers assembled coherently.
Typically, at the proximal end of the image-forwarding system is an ocular lens that creates a virtual image for direct human visualization. Often a camera means, such as a charge coupled device (CCD) chip or a CMOS device is mounted to the endoscope. The camera means receives the image and produces a signal for a video display. While surgeons can, and often do, look directly into the endoscope through an ocular lens, it is more common for them to use an attached camera and observe an image on a video screen. In conventional and video camera arrangements, the camera (hereinafter referred to as a “camera head”) is usually detachably connected to the endoscope. A camera control unit (CCU) is employed to provide, among other controls, a link between the camera head and the video display.
As the camera head is detachable from the endoscope, this necessitates a coupling mechanism to transmit, for example, data and/or optical energy (i.e. illuminating light) between the endoscope and detachable camera. However, it would be advantageous to eliminate the need for a coupling mechanism to transmit optical energy between the endoscope and detachable camera as misalignment, dirt/debris and damage to the optical path at the coupling location can reduce the efficiency of the optical path. However, the generation of optical energy in the endoscope has not been feasible because to the corresponding increase in weight of the endoscope when a power source (e.g. a battery) is positioned on the endoscope. Accordingly, a system that provides for the generation of optical energy in the endoscope is desired that does not significantly increase the weight and size of the endoscope is desired.
Some video endoscope systems have provided a coupling mechanism between the endoscope and the camera that includes, for example, a stem/receptacle arrangement for transmitting illuminating light from the camera to the endoscope and a stem/receptacle arrangement for transmitting image data from the endoscope to the camera. However, this arrangement does not necessarily provide an easy way to pan the endoscope. For instance, as the endoscope and camera are locked together, the surgeon has to rotate his/her wrist to achieve a panning effect. This only allows for limited rotation, i.e. a wrist cannot be rotated indefinitely, and causes disorienting image spin as the camera and endoscope are rotated as a single unit during panning.
Various systems have tried to address the issue of allowing relative rotation between the endoscope and camera with limited success. A challenge faced by designers is that as the shaft rotates relative to the camera, either the illumination system or the image optical system has to rotate around a central axis. Typically the image optical system is placed in the center, i.e. defines the central axis of the endoscope, and the illumination system is eccentric to the image optical system, causing the illumination system to move concentrically about the central axis of the endoscope as the shaft is rotated/panned. This rotatable illumination system makes it difficult to transfer light from the camera to the endoscope. One design has the portion of the illumination system that is housed in the camera be movable to follow the motion of the shaft. This requires the light conduit to wind up inside the camera head. It cannot, however, be wound indefinitely, and therefore it is necessary to limit the panning range. This limitation can be annoying to surgeons because once the limit is reached, the device has to be panned back the opposite direction to reach the viewing destination. Additionally, mechanical wear associated with repeated winding and unwinding of the illumination conduit is problematic, as well as “sealing” any moving parts to prevent undesired “leakage” of high intensity light from coupling.
Another design is based on what could be called an illumination slip ring where fibers are splayed out in a circular arrangement and will thus receive light regardless of rotational position. One could also use LEDs arranged in a circle. This optical slip-ring design is unfortunately difficult to manufacture and typically has problems of low efficiency, excessive and/or unsafe heat build-up, and non-uniform illumination.
Because of these many problems, endoscope designers have looked at placing the illumination source, which traditionally has been an external bulb providing light through an external light guide, inside the endoscope shaft. LEDs have been used to provide illumination. However, utilizing LEDs requires electrical power to the LEDs themselves. Arguably, electrical slip rings are more tried and true than optical slip rings, but electrical slip rings typically have problems with wear, electromagnetic noise, and reliability. Further, in a surgical/medical setting, there is the additional safety concern of electrical power transfer across an open rotating interface. The main drawback with a design which puts the light source in the endoscope however, is that it is not compatible with current endoscopic systems already in the field.
It should further be noted that endoscopes come in a variety of sizes for particular applications and surgical procedures. The telescope lens system may have a variety of optical properties. For example, the objective lens may include a prism whereby the image viewed is at some angle with respect to that of the axis of the telescope. Also, different endoscopes may have different fields of view (FOV). These and other variations affect the optical properties of particular endoscopes.
As above noted, the camera head is usually detachable from the endoscope, and is often conveniently constructed so as to be attachable to a variety of endoscopes having differing optical properties. For this reason, a CCU receiving a video signal from an attached camera head will need to know the endoscope optical properties in order to present an optimized image on the video monitor. Currently, the settings of the camera head and CCU are manually adjusted to the endoscope's optical properties.
It would be advantageous to simplify the task of using the endoscope and video camera system by eliminating the need to make manual adjustments to the camera head and/or CCU in order to optimize the video camera system settings for an attached endoscope.
To ensure optimal video system operation utilizing a particular endoscope, it is also necessary that the endoscope undergo periodic scheduled and unscheduled maintenance. Further, most endoscope manufacturers require their products to be maintained properly to assure reliable, accurate and precise functionality. This enhances the manufacturer's reputation and the reliance of health care professionals on the manufacturer's products. From a manufacturer's perspective, it is important that only factory authorized personnel service their products; however, it is a reality in the marketplace that some medical facilities may use unauthorized repair services. It is to a manufacturer's advantage to discourage such sub-optimal maintenance because if maintenance is performed incorrectly, medical personnel may attribute problems caused by the incorrectly performed maintenance to the product and/or manufacturing design.
Related to the maintenance of the endoscope are the usage characteristics of the endoscopes. For a manufacturer, how its products are used is valuable information. A manufacturer may want to know, for example, how often each product is used, the elapsed time of each use, the maintenance history of the product, and so on. These factors can impact future endoscope design related to durability, reliability, components and materials used in the manufacturing process.
It is known in the art to utilize electronic sensors to record operating conditions beyond the endoscope's recognized safe operating range to which it has been subjected. Peak values for conditions such as, pressure, humidity, irradiation, and/or shock or impact loads to which the endoscope has been exposed may be recorded. Upon failure of the endoscope, this information may then be utilized to determine the probable cause of the failure.
U.S. Pat. No. 5,896,166 to D'Alfonso et al. (“the '166 patent”) and U.S. Pat. No. 6,313,868 to D'Alfonso et al. (“the '868 patent”), both disclose storing camera parameters and camera use characteristics in a non-volatile memory located in the camera head and transmitting the camera parameters and camera use characteristics to a camera control unit through a data coupling upon connection of the camera unit to a camera control unit. However, neither reference discloses a system where the endoscope has a memory device located in it, so that a single camera unit may be interchanged with a plurality of endoscopes and whereupon connection of the camera unit will automatically read the endoscope parameters and use characteristics. Further, neither the '166 nor the '868 patent discloses a system where the endoscope use characteristics can be updated to log a history of the particular endoscope use. Rather, both the '166 and the '868 patents are limited to updating only the camera unit. Still further, neither the '166 nor the '868 patent discloses a system wherein the endoscope parameters and use characteristics can be read automatically through non-contact transmission.
Another problem in the field of endoscope management is that of keeping track of the many different endoscopes used throughout the facility. There have been various approaches to keeping track of the locations and inventory of endoscopes. Simple inventory control and sign-out sheets are labor intensive and inaccurate, and, as a result, are ineffective for assuring the level of scrutiny that is required for medical equipment. Further, sign-out sheets do not allow for monitoring equipment, for example, determining whether the endoscope is functioning properly or needs maintenance.
Bar codes have been used for tracking purposes. Bar coding of equipment allows identification and locating of the equipment by reading the bar code with a portable bar code scanner. However, bar coding is ineffective when the equipment has been moved since the last time that it was scanned. Moreover, the use of bar codes can require the labor-intensive step of touring the facility with one or more portable scanners in search of endoscopes. Further, bar codes, like sign-out sheets, do not allow for the monitoring of equipment, for example, determining whether the endoscope is functioning properly or needs maintenance.
It is known in the art that energy and data transmission can take place through an inductive coupling in which high frequency coils act like a loosely coupled transformer as disclosed in U.S. Pat. No. 6,092,722 to Heinrichs et al. (“the '722 patent”). The high frequency coil, when power is applied to it, produces a high frequency field, which will be imposed upon the high frequency coil of another device when brought into close proximity.
One major problem with the use of inductive coupling as disclosed in the '722 patent is that it can create unacceptable levels of electro-magnetic interference (“EMI”) in the operating room environment. Electronic equipment, such as the video signals transmitted from the camera head to the camera control unit, can be particularly sensitive to EMI. Therefore, to reduce the negative effects of EMI, adequate shielding should be provided. This, however, significantly adds to the cost and manufacturing time of the device. Therefore, a system that does not produce EMI is greatly desired.
Another disadvantage with the use of inductive coupling as disclosed in the '722 patent is that it necessitates the use of inductive coils both in the endoscope and the camera head adding greatly to the size and the weight of the devices. In addition to the added size and weight of the inductive coils, the necessary shielding for the EMI produced by the inductive coils will further increase the device size and weight. Endoscopes and camera heads that are lighter, smaller and easier to handle are desired.
Another disadvantage to the inductive coupling technique as disclosed in the '722 patent is because high frequency coils act like a loosely coupled transformer, both high frequency coils should be aligned one directly on top of the other in order to achieve an effective data transfer. The inductive field created by the high frequency coils is unidirectional and therefore accurate alignment of the component is important. This situation could be very frustrating for medical professionals, having to spend time trying to accurately align the camera head and endoscope to have the video system function properly. Therefore, a system that does not require precise alignment of the components is desired.
Radio frequency identification (“RFID”) has been used to locate various devices and/or equipment. However, RFID used in the operating room environment has been limited due to the large power ranges required for locating the device. RFID utilized for locating purposes necessitates using a transceiver with as large a power range as is reasonable. A large power range, unfortunately, may cause receipt of the signal by unintended RFID receivers. That is, if an endoscope is in use in room A, it is undesirable to have unrelated endoscope equipment in room B “respond” to the transceiver. RFID has been limited to tracking the location of devices and/or equipment, facilitating only one-way communication from the device and/or equipment to the recording or tracking system.
While RFID has the advantage of having a relatively rapid read rate, one particular limitation RFID has encountered is accuracy of scans in relatively harsh environments. For example, RFID has been known to struggle with getting an accurate read through or near liquids and metals.
Therefore, a system is needed that simplifies and optimizes endoscope and video camera usage and does not interfere with sensitive electronic equipment, encourages customers to maintain the endoscope to manufacturer's parameters and provides the endoscope manufacturer with information regarding product usage and maintenance.